Sambou Bamboo salt™ down-regulates the expression levels of angiotensin-converting enzyme 2 in activated human mast cells.

Mast cells have a detrimental impact on coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Sambou Bamboo salt™ (BS) suppresses mast cell-mediated inflammatory response and enhances immunity. In this study, we investigated the regulatory effects of BS on expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease/serine subfamily member 2 (TMPRSS2) in human mast cell line (HMC)-1 cells. BS resulted in significant reductions in expression levels of ACE2 and TMPRSS2 in activated HMC-1 cells. Levels of tryptase were reduced by BS. In addition, BS blocked activation of activator protein 1 (AP-1), c-Jun NH2-terminal kinases (JNK), p38, and phosphatidylinositide-3-kinase (PI3K) in activated HMC-1 cells. Therefore, these results show that BS reduces levels of ACE2, TMPRSS2, and tryptase by inhibiting AP-1/JNK/p38/PI3K signaling pathways in mast cells. These findings can serve as valuable foundational data for the development of therapeutic agents aimed at preventing SARS-CoV-2 infection.